Pool season · California
Irvine Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
This is the one-page view of Irvine's pool year: both model windows, the estimated water-temperature curve, and today's live position on the season bar. The detailed checklists live on the opening and closing guides; this page is the calendar you check between them.
Irvine, CA — 136 swim days a yearEach dot on the bar is one week of Irvine's typical year, colored by what the model says that week is for: gray weeks are off-season, hollow teal marks the opening window (March 17–April 7), solid teal is swim season, and hollow amber is the closing window ending November 27. The black marker is today — its position against the colors is the entire executive summary.
The Irvine pool calendar
Opening — target March 24
Target March 24; the practical window runs March 17–April 7, and the 7-day mean crosses the 61°F threshold around April 7. Cold-water starts are the cheap ones.
Closing — deadline November 27
The window opens November 17 once water leaves the algae zone; the model deadline is November 27, a week ahead of the December 25 freeze normal.
Estimated water temperature by month
This is Irvine's typical-year water curve: the same EWMA model as the live widget, run on the 1991–2020 normals instead of this week's weather.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 56° | 56° | 59° | 61° | 64° | 67° | 71° | 75° | 75° | 72° | 65° | 58° |
The curve peaks near 75°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Inglewood's pool season and Jurupa Valley's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the California season index.
Irvine pool season FAQ
When should I open my pool in Irvine, CA?
Target March 24. That date backs off two weeks from the day Irvine's 7-day mean temperature reaches 61°F, so you start up in cold, algae-resistant water. Work the full checklist in the Irvine opening guide.
When should I close my pool in Irvine?
The closing deadline is November 27 — late enough that the water has cooled out of the algae zone, early enough to beat Irvine's first-freeze normal by about a week. See the Irvine closing guide for the winterizing steps.
How long is the swim season in Irvine?
Irvine averages 136 days a year with normal highs of 80°F or better — about 8 days earlier than the California median. The California season index ranks all 147 covered cities by the same metric.
How warm does pool water get in Irvine?
An unheated pool near Irvine typically peaks around 75°F in high summer and bottoms out near 56°F in winter, never quite reaching the 78°F comfort line without a heater or solar cover. The month-by-month curve above shows the whole cycle; the methodology page explains the ±5°F error bars.
Email me when Irvine hits the closing window
Data: NOAA 1991–2020 climate normals via Tustin Irvine Rch (2.1 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.